1. Field of the Invention
The present invention relates in general to building construction materials and particularly relates to stacked siding which is locked in place at its upper and lower edges.
2. Description of Prior Developments
Aluminum siding and plastic siding have been used for many years to provide a decorative and protective covering for the exterior walls of various structures, including industrial, commercial and residential buildings. Although prior siding configurations have, in general, performed satisfactorily, a recurring problem persists wherein strong winds, external impact or vandalism causes adjacent siding panels to disengage from one another and separate. Once separated, the panels not only create an unpleasant nonuniform appearance but also produce undesirable noise as they flap against one another in strong winds.
In order to prevent such disengagement, prior siding designs have relied upon various tongue and groove interconnections wherein the tongue or lip of one siding panel is resiliently deflected during insertion into a groove or channel on an adjacent panel. Although such spring biased frictional engagement presents an improvement over other prior designs, the panels still can become disengaged under high external loading if they are installed incorrectly.
Proper installation necessitates holding a panel in a totally engaged upward position before nailing. The end result of not properly holding a panel up during nailing is not discernible until it becomes totally engaged from a lower locking tab due to high wind, vandalism, etc. Holding a siding panel too tightly upward during nailing can result in subsequent rippling of the siding, especially when changes in the ambient temperature cause the panels to expand or contract. Holding a panel too loosely during installation also causes subsequent disengagement. Thus, a certain degree of skill is needed for proper installation.
Another drawback associated with prior siding designs is the difficulty experienced during installation of knowing when one siding panel is properly positioned and interengaged with another prior to nailing. That is, an installer is required to insert a loose siding panel into an adjacent panel which has been previously secured to a building by nailing and hope that the loose panel is properly positioned.
During such installation, the installer has to push the loose siding panel upwardly along the side of a building until the installer believes the siding panel is in full abutting engagement or "bottomed out" against and within the adjacent siding panel and then hold the panel in place while nailing it. This is quite a difficult task, especially when working with long lengths of siding which are not only cumbersome but also quite heavy, considering that the panel is held by only the thumb and second finger.
Clearly, this prior method of installation requires experience and skill to fully perfect and is therefore not particularly well adapted to practice by unskilled installers.
An aluminum siding stack-on panel is known which is wind vulnerable and, in fact, is known to come loose if an installer does not fully seat each panel. Sometimes an installer lifts the panels upward in an attempt to correct misalignments.
Another drawback associated with plastic siding is the difficulty of ensuring proper penetration of the mounting nails which fasten the siding to a building. Vinyl siding is typically allowed to shift a limited amount toward and away from its underlying wall by only partially driving and seating the mounting nails into the wall.
This technique leaves a portion of the nail shank extending above the wall surface and allows for some shifting and self-alignment of the siding against the wall, particularly in the case of warped wall surfaces. However, it is not uncommon for an unskilled installer to fully seat the nail against the siding panel thereby preventing the siding from shifting.
Accordingly, a need exists for a siding panel which is easy to install, which resists disengagement from an underlying panel during installation and which controls the extent of nail penetration so as to ensure a predetermined extent or length of nail projection above the nailing surface of the siding panel.
A further need exists for a siding panel which provides a positive locking engagement between adjacent siding panels, and which may be readily installed by relatively unskilled workers.